Seattle viaduct’s days are numbered

Seattle council members were briefed during Tuesday’s Sustainability and Transportation Committee about plans to demolish the Alaskan Way Viaduct, now that a tunnel to replace it is steadily coming along. A shorter timeline than previously detailed was discussed at the meeting with two significant updates:

New tunnel will be “substantially” complete by the end of October (that could change), according to WSDOT — (three years late from the original deadline).

Demolition of the Alaskan Way Viaduct could begin in early 2019.

“We anticipate right now with that schedule, to start substantial demolition in early 2019,” said Joe Hedges, Alaskan Way Viaduct administrator with the Washington State Department of Transportation. “We might do some selective demo to help ourselves out a bit (before 2019).”

In January 2018, WSDOT will issue a request for proposal, seeking companies to demolish the viaduct. It expects to award a contract in the spring. The timing of the demolition is dependent on the opening of the tunnel. If the tunnel does open in October 2018, then demolition could begin shortly thereafter. WSDOT says the opening date is still predicted at early 2019.

Alaskan Way Viaduct demolition

The demolition project is expected to take about nine months. WSDOT plans to have the viaduct demolished in sections. Its main priority will be demolishing portions of the structure north of Pike Street and around the Columbia on-ramp.

The department is currently planning for how to clear out cars and people from below the structure while work is underway. WSDOT is also planning to mitigate noise, dust and other issue presented by the project.

During the demolition, WSDOT aims to move Alaskan Way from under the structure. It wants to keep one lane open to keep goods and people moving. Cross street closures (underneath the viaduct) will be limited to 30 days.

The demolition project has been combined with two other related jobs — shutting down the Battery Street Tunnel and reconnecting surface streets around Thomas and John streets across Aurora Avenue. Those roadways were previously disrupted by construction.

Correction: A previous version of this report indicated the replacement tunnel could open in mid-October. WSDOT says the tunnel could be finished then, but crews must realign the tunnel with SR 99 before it opens to the public. That opening date remains early 2019.